Power transformer testing and commissioning are critical stages in ensuring the reliability, safety, and optimal performance of power transformers in electrical networks. The process involves a series of tests and procedures conducted at different stages, from manufacturing to installation.
Here are the key stages of power transformer testing and commissioning:
1. Factory Acceptance Testing (FAT):
1.1. Purpose: To ensure that the transformer meets specified design and performance criteria before it is shipped to the installation site.
1.2. Tests Conducted:- Measurement of winding resistance. – Turns ratio test. – Insulation resistance test. – Excitation current test. – Polarity and phase-relation test. – Impedance voltage and load loss test.
2. Transportation and Handling:
2.1. Purpose: To verify that the transformer has not been damaged during transportation and handling.
2.2. Activities:- Visual inspection for external damage. – Checking oil levels and integrity of bushings.
3. Site Acceptance Testing (SAT):
3.1. Purpose: To confirm that the transformer was not damaged during transportation and to ensure it is ready for installation.
3.2. Tests Conducted:- Insulation resistance test. – Transformer turns ratio test. – Winding resistance measurement. – Polarity and phase-relation test.
Dielectric tests, including power frequency withstand voltage test.
4. Installation and Pre-commissioning:
4.1. Purpose: To ensure that the transformer is properly installed and connected to the electrical system.
4.2. Activities:- Checking oil levels and filling if necessary. – Checking and tightening electrical connections. – Verifying correct tap changer operation.
5. Energization and Functional Tests:
5.1. Purpose: To verify the transformer’s performance under load conditions and ensure proper functioning.
5..2. Tests Conducted:- Load loss and impedance tests. – Measurement of no-load loss and current. – Short circuit withstand test. – Temperature rise test.
6. Oil Filtration and Treatment:
6.1. Purpose: To ensure the transformer’s insulating oil meets specified cleanliness and dielectric strength requirements.
6.2. Activities:- Filtration of the transformer oil. – Testing for dielectric strength and moisture content.
7. Commissioning Tests:
7.1. Purpose: To validate the transformer’s performance and integration into the overall electrical system
7.2. Tests Conducted:- Voltage ratio test.Vector group verification. – Parallel operation test (if applicable). – Verification of protective relay settings.
8. Site Documentation and Handover:
8.1. Purpose: To provide comprehensive documentation of the testing and commissioning process for future reference and to facilitate the handover to the end-user.
8.2. Activities:- Compilation of test reports and documentation. – Training for operating and maintenance personnel. – Handover of all relevant documentation.
The testing and commissioning of power transformers are integral to ensuring the reliability, safety, and efficiency of electrical power systems. These stages involve a combination of factory and site-based tests, inspections, and procedures to confirm that the transformer meets specified standards and performs as intended within the operational environment